ESR1 and neoplasm: Prognostically, the most important factors are the histological type, size of the tumor, tumor necrosis, skin, nipple and chest wall invasion, lymphovascular invasion, grade, stage, estrogen receptor (ER) status, progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2), cell proliferation marker (ki-67), and type of therapy [4,5-6].